#list1 = [1,2,3,2]

#a = list1[0]

#for i in list1:
#    if i > a:
#        a = i
#print(a)


#list2 = [1,2,3,4,'a',1,'b',21]

#sum = 0

#for i in list2:
#    if isinstance(i,int):
#        sum = sum + i
#print(sum)


#x = 6
#for i in range(1,x):
#    if x % i == 0:
#        print("不是素数")
#3    break
#else:
#    print("是素数")

x = 5
sum = 0
for i in range(2,x+1):
    for j in range(2,i):
        if i % j == 0:
            break
    else:
        sum =sum + 1
print(sum)